1. Field of the Invention
The present invention relates to a winding apparatus for winding a wire around a deflection yoke frame to obtain a saddle type coil or the like. The present invention also relates to a work winding method therefor.
2. Description of the Related Art
A conventional deflection yoke frame of a deflection yoke used in a conventional television receiver has two deflection frame halves. A vertical coil is wound around one of the deflection frame halves and a horizontal coil is wound around the other. The two halves are assembled to form a deflection coil on a single funnel-like deflection yoke frame. Accordingly, it is relatively easy, because of the two-part construction, to wind a saddle type coil or the like on the deflection yoke frame.
However, today, the so called "high vision" type television receiver has come into wide spread use. In this type of television the deflection yoke frame is formed as a one-piece funnel-like shaped unit. For this reason, it suffers from the drawback that winding of the coil is difficult. Various winding devices and winding methods have been proposed to overcome this difficulty.
FIG. 1 is a perspective view showing one example of a deflection yoke frame of the conventional high vision type of television receiver.
A deflection yoke frame 21 shown in FIG. 1 has a generally funnel-like shape that gradually increases in diameter toward one end. A large opening portion 21a is disposed near a fluorescent display surface side of a cathode ray tube, while the small opening portion 21b is disposed on the narrow neck side of the cathode ray tube.
A plurality of retaining pieces 21c, a plurality of winding grooves 21d and a single opening-portion circumferential groove 21e are provided on the side of the opening portion 21a of the deflection yoke frame 21, whereas a plurality of retaining pieces 21f, winding grooves 21g and opening-portion circumferential groove 21e are provided on the side of the opening portion 21b of the deflection yoke frame 21. A wire is wound on an inner circumferential surface of the deflection yoke frame 21 to form a saddle type coil.
FIGS. 2 and 3 show an example of the winding steps used in forming a saddle type coil 9a by winding a wire 9 around the deflection yoke frame 21. An explanation will be made as to the winding operation with reference to FIGS. 2 and 3 wherein reference numeral 4 denotes a nozzle unit on the winding device side, and reference numeral 5 denotes a guide unit on the winding device side.
A free end of the wire 9 is first gripped by a nozzle 18 of the nozzle unit 4. The nozzle unit 4 is lowered down to the opening portion 21b through a center of the deflection yoke frame 21, the free end of the wire 9 is clamped in this position by retaining unit (not shown), and the free end is retained by a retaining portion 21k provided at a predetermined position of the opening portion 21b.
Subsequently, the guide unit 5 is used to pick up the wire 9 and withdraw it so that the wire 9 does not become hooked on the retaining piece 21f when the yoke 21 is rotated. The wire 9 is then caused to extend through the groove 21g from one retaining piece 21f to a predetermined retaining piece 21f and is raised through the center of the deflection yoke frame 21 from the retaining piece 21f'. The wire 9 is thereafter caused to extend from the retaining piece 21c provided at a predetermined position on the side of the opening portion 21a of the deflection yoke frame 21 to a predetermined retaining piece 21c' through the opening-portion circumferential groove 21e. The wire 9 is then lowered through the center of the deflection yoke frame 21 from the retaining piece 21c' and returned back to the retaining piece 21f in order. This process is repeated to obtain a predetermined number of windings. Finally, the retaining unit clamps the free end of the wire 9 to a predetermined retaining portion 21k and then cuts it to form a single saddle type coil 9a. Thus, a plurality of saddle type coils are provided on the inner surface of the deflection yoke frame 21 to form a deflection coil assembly. Details of the above-described winding method are disclosed in pending U.S. Pat. No. 5,484,113 issued on Jan. 16, 1996 in the name of Watanabe. The content of this patent is hereby incorporated by reference thereto.
In the structure shown in FIGS. 2 and 3, the retaining portions 21k are formed in the deflection yoke frame 21 in advance. However, in some cases, these retaining portions 21k are not formed. In such cases the retaining pieces 21c are used to perform both functions. In those cases where the wire is clamped to the retaining pieces 21c, the opening-portion circumferential groove 21e is too narrow to allow the formation of a large number of windings.
As described above, in the conventional winding apparatus in the event that the entangling or retaining portions are not provided at predetermined positions of the deflection yoke frame 21, a method of retaining/clamping the wire 9 at the retaining pieces 21c is used. However, the convention winding apparatus suffers from the drawback that it is impossible to set a predetermined length of the wire 9 because it is necessary to avoid the reduction of an effective width of the opening-portion circumferential groove 21e. In other words, the conventional apparatus suffers from the problem that the length of wire 9 which can be retained corresponds to only two or three turns, and it is impossible to withdraw a length of the wire 9 sufficient to fix the free end of the wire 9 to a fixed pin (not shown) located at a predetermined position.